Multi-step method of nondestructively measuring a region within an ultra-hard polycrystalline construction

ABSTRACT

A method for nondestructively obtaining measurement information of a region within one or more ultra-hard polycrystalline constructions comprises conducting a first measurement using x-ray fluorescence by directing x-rays onto a surface of the diamond body, receiving x-ray fluorescence from the diamond body, and deriving measurement information regarding the region therefrom. A second method can be used on the same or other ultra-hard polycrystalline constructions to obtain measurement information regarding the region in a manner that is relatively more time efficient than the first method to facilitate use of the measurement method on a large number of constructions. The second measurement can be selected from the group including beta backscatter, x-ray radioscopy, eddy current, magnetic induction, and microresistance. In an example embodiment, the method is used to determine the thickness of a region within the diamond body that comprises less catalyst material than another region within the body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/745,958 filed May 8, 2007, which claims the benefit of U.S.Provisional Application No. 60/799,137 filed May 9, 2006, which areherein incorporated by reference in their entirety.

BACKGROUND

1. Field of the Invention

This invention relates to nondestructive methods developed for measuringthe thickness or variation in thickness of a region within a materialmicrostructure and, more specifically, to a multi-step method ofmeasuring the thickness or variation in thickness of one or more regionin ultra-hard polycrystalline constructions.

2. Background of the Invention

The formation of constructions having a material microstructure made upor two or more different layers or regions of materials is well known.Such constructions are intentionally engineered in this fashion toprovide a desired mix of physical, mechanical and/or thermal propertieswithin the material microstructure, making it better equipped to handlea particular end use application. In order to provide such desiredproperties in a predictable and consistent manner, the thickness orvariation of thickness of each engineered region must be controlled.

It is, therefore, necessary that the thickness of each such regionwithin the construction be measured for the purpose of both controllingthe process that is used to make the construction, to ensure itsconsistency and for controlling the quality or ability of theconstruction to perform as expected. Methods useful for measuring thethickness or variation in the thickness of a region within a materialconstruction will vary depending on the nature of the construction. Formaterial constructions used in tooling, wear, and cutting applicationsprovided in the form of an ultra-hard polycrystalline material, e.g.,comprising polycrystalline diamond, a useful method for measuring thethickness or variation of thickness of one or more region within theconstruction is by destructive method or destructive testing.

Destructive testing requires that the construction itself be cut orotherwise treated in a manner that physically exposes the differentregions therein so that they can be measured by visual inspection. In anexample embodiment, where the construction is one comprising anultrahard polycrystalline material such as diamond or cubic boronnitride, the construction itself is cut, e.g., in half, so that thedifferent regions forming the construction can be viewed visually forpurposes of measuring the thickness or variation of thickness of theregions. In an example embodiment, such visual indication is made withthe assistance of a magnifying device such as a microscope, e.g., ascanning electron microscope.

While such destructive test method is useful for determining thethickness or variation of thickness within a construction, it is timeconsuming in that after the part is cut it must usually be furtherprepared by grinding, polishing or the like, then mounted formicroscopic evaluation, and the microscopic evaluation must be takenover a number of different points to gather sufficient data to arrive ata numerical value, e.g., an average region thickness throughout thepart. Further, the use of such destructive test method is expensive, andresults in the parts that are measured being destroyed, therebyadversely impacting the economics of making the parts.

It is, therefore, desired that a method be developed that is capable ofmeasuring the thickness or variation of thickness within a region of amaterial construction, e.g., an ultra-hard polycrystalline construction,in a manner that is not destructive. It is further desired that such amethod be capable of providing such a desired measurement in a mannerthat has a consistent degree of accuracy. It is further desired that themethod be capable of providing an indication of the region thickness atdifferent locations within the construction, and enable efficienttesting on a large-scale production basis.

SUMMARY OF THE INVENTION

A method for nondestructively obtaining measurement information,according to principles of this invention, as it relates to a particularregion or interface within an ultra-hard polycrystalline construction.In an example embodiment, the ultra-hard polycrystalline constructioncomprises a polycrystalline diamond body, and the measurementinformation relates to a region within the polycrystalline diamond bodythat comprises less catalyst material than otherwise present in anotherregion of the polycrystalline diamond body.

In an example embodiment, the method comprises conducting a firstmeasurement by using x-ray fluorescence by directing x-rays onto asurface of the diamond body, receiving x-ray fluorescence from thediamond body, and deriving measurement information from the receivedx-ray fluorescence. In an example embodiment, the x-rays are provided tocause target atoms in the diamond body to emit x-ray fluorescence, andin a preferred embodiment, the region comprising less catalyst materialcomprises less target atoms. Accordingly, target atoms include thosematerials selected from Group VIII elements of the Periodic table. Thisfirst measurement technique can be used to determine the interface ofthe region comprising less catalyst material, and to provide measurementinformation sufficient to generate a plot or map of the interface alonga desired surface area.

A second measurement technique can be used to conduct a secondmeasurement on the same ultra-hard polycrystalline construction or onanother ultra-hard polycrystalline construction, wherein the otherultra-hard polycrystalline construction can be produced in the samebatch as the one measured using the first measurement technique, thusbeing expected to have a measured interface that is generally similar tothat of the construction measured by the first measurement technique. Inan example embodiment, it is desired that the second measurementtechnique be one that can provide measurement information relativelymore quickly than the first measurement technique to facilitate themeasurement of a number of constructions. Thus, in a preferredembodiment, the second measurement technique is different than that usedto conduct the first measurement, and can be one selected from the groupconsisting of beta backscatter, x-ray radioscopy, eddy current, magneticinduction, and microresistance.

In an example embodiment, the region comprising less catalyst materialextends a depth from a surface of the diamond body, and the remainingregion of the diamond body includes the catalyst material. Themeasurement information is provided to determine the thickness of theregion comprising less of the catalyst material. The method of thisinvention enables one to obtain measurement information regarding aregion within an ultra-hard polycrystalline construction in anondestructive manner that is accurate, and that can be implemented on alarge scale to provide such measurement information for a plurality ofsuch constructions in a manner that is relatively time efficient.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will beappreciated as the same becomes better understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings wherein:

FIG. 1 is schematic view of an ultra-hard polycrystalline constructionprovided in the form of a compact;

FIG. 2 is a cross-sectional side view of the ultra-hard polycrystallineconstruction taken along a section of FIG. 1;

FIG. 3 is a schematic side view of an X-ray fluorescence device usefulfor determining the thickness and/or variations in thickness of a regionwithin the ultra-hard polycrystalline construction of FIGS. 1 and 2;

FIG. 4 is a measurement result taken from the X-ray fluorescence deviceof FIG. 3;

FIG. 5 is a schematic view of a Beta Backscatter device useful fordetermining the thickness and/or variation in thickness of a regionwithin the ultra-hard polycrystalline construction of FIGS. 1 and 2;

FIG. 6 is a schematic view of an X-ray radioscopy device useful fordetermining the thickness and/or variation in thickness of a regionwithin the ultra-hard polycrystalline constructions of FIGS. 1 and 2;

FIG. 7 is an X-ray image taken of an ultra-hard polycrystallineconstruction using the X-ray radioscopy device of FIG. 6;

FIG. 8 is a schematic view of an eddy current device useful fordetermining the thickness and/or variation in thickness of a regionwithin the ultra-hard polycrystalline constructions of FIGS. 1 and 2;

FIG. 9 is a schematic view of a magnetic induction device useful fordetermining the thickness and/or variation in thickness of a regionwithin the ultra-hard polycrystalline constructions of FIGS. 1 and 2;

FIG. 10 is a perspective side view of an insert, for use in a rollercone or a hammer drill bit, comprising the ultra-hard polycrystallineconstruction measured using the nondestructive method of this invention;

FIG. 11 is a perspective side view of a roller cone drill bit comprisinga number of the inserts of FIG. 10;

FIG. 12 is a perspective side view of a percussion or hammer bitcomprising a number of inserts of FIG. 10;

FIG. 13 is a schematic perspective side view of a shear cuttercomprising the ultra-hard polycrystalline construction measured usingthe nondestructive method of this invention; and

FIG. 14 is a perspective side view of a drag bit comprising a number ofthe shear cutters of FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

A nondestructive method useful for determining the thickness orvariation of thickness within an ultra-hard polycrystallineconstruction, according to the principles of this invention, is oneusing two or more different nondestructive measurement techniques. In anexample embodiment, a first nondestructive measurement technique used isX-ray fluorescence (XRF). As described in greater detail below, XRF isused to provide detailed thickness and/or variation in thicknessinformation within a targeted region of the ultra-hard polycrystallineconstruction in a manner that is accurate and that does not result inthe destruction of the part. If desired, XRF can be used to generatethickness information for an entire region within the construction andproduce a topographic map illustrating the thickness and any variationin thickness along this region.

In an example embodiment, a second nondestructive measurement techniqueor method is used for the purpose of screening large numbers of parts,e.g., ones that are of a family of parts, wherein at least one part ofthe family has already been measured by the XRF method. The secondnondestructive measurement technique is preferably one that can beperformed relatively more quickly than XRF to facilitate the rapidmeasurement of many parts, and thus one that would be suitable formeasuring a large number of parts in production to provide an indicationwhether the target region thickness for each measured part meets adesired target or set point thickness. In an example embodiment, thesecond nondestructive measurement technique can be performed using BetaBackscatter (BB). In another example embodiment, the secondnondestructive measurement technique can be performed using X-rayRadioscopy (XRR).

FIG. 1 illustrates an ultra-hard polycrystalline construction 10. Theconstruction generally comprises a body 12 formed from an ultra-hardpolycrystalline material 14, e.g., comprising diamond, polycrystallinediamond (PCD), cubic boron nitride (cBN), polycrystalline cubic boronnitride (PcBN), and mixtures thereof. The body 12 mayor may not beattached to a substrate. In the example embodiment illustrated in FIG.1, the construction includes a substrate 15 that is joined together withthe body 12 to form a compact.

The substrate can be formed from a variety of different materials suchas those useful for forming conventional PCD compacts, like ceramicmaterials, metallic materials, cermet materials, carbides, nitrides, andmixtures thereof. When the ultra-hard polycrystalline constructioncomprises polycrystalline diamond, a preferred substrate materialcomprises cemented tungsten carbide (WC—Co).

FIG. 2 illustrates a cross-sectional view of a section taken through theultra-hard polycrystalline construction 10 of FIG. 1, illustrating thematerial microstructure of the construction and its different regions.In an example embodiment, the body 12 includes a first region 16, thatextends a depth “D” into the body from an outside body surface 18, and asecond region 20, that extends from the first region 16 to the substrate15. An interface 22 within the body defines the point of transitionbetween the first and second regions 16 and 20.

While a particular polycrystalline construction 10 has been illustratedin FIG. 2, having first and second regions occupying particularlocations of the construction, it is to be understood that constructionshaving first and second regions that are positioned differently thanthat illustrated in FIG. 2 can also be measured using the methods ofthis invention. For example, nondestructive measuring methods of thisinvention can be used for measuring regions in an ultra-hardpolycrystalline construction that are positioned at locations other thanon the construction front side surface or table, e.g., along a sidewallsurface of the construction.

In an example embodiment, the body 12 is formed from PCD and the firstregion 16 includes PCD that has been treated so that it is substantiallyfree of a catalyst material, e.g., a solvent metal catalyst, used toform the PCD. As used herein, the term “substantially free” isunderstood to mean that the catalyst material is removed from the firstregion, in which case the first region has a material microstructurecomprising a polycrystalline diamond matrix phase and a plurality ofvoids interposed therebetween. The term “substantially free” is alsounderstood to include treatments that render the catalyst material usedto form the PCD no longer catalytic, such as by reacting the catalystmaterial to form a noncatalytic compound and/or by encapsulating thecatalyst material with another material that prevents the catalystmaterial from functioning as a catalyst with the polycrystalline diamondmatrix phase when the construction is subjected to a cutting, tooling orwear application.

The catalyst material used to form the diamond phase in the constructionmicrostructure can be the same as that used to form conventional PCD byhigh pressure/high temperature (HPHT) sintering process. Such catalystmaterials include metals from Group VII of the Periodic table, withcobalt (Co) being the most common. In an example embodiment, thecatalyst material is a solvent metal catalyst such as Ni, Co, Fe, andcombinations thereof. The catalyst material can be removed by chemical,electrical, or electrochemical processes. In an example embodiment, thecatalyst material is Co and is removed from the first region by acidleaching process.

In an example embodiment, it is desired that the depth “D” of the firstregion within the body be controlled to provide consistent andrepeatable characteristics of mechanical and thermal performance for theconstruction. As explained in greater detail below, it is thereforenecessary to develop an accurate and repeatable technique for measuringthe depth of the first region in the construction to ensure theconsistency of such desired performance characteristics.

In an example construction, the body second region 20 comprises PCD thatincludes the catalyst material. The second or PCD region 20 has amaterial microstructure comprising a polycrystalline diamond matrix andthe catalyst material disposed interstitially within the matrix. In anexample embodiment, the substrate 15 is attached to the body 12 at theinterface with the body second region 20.

The depth of the first region can be controlled by adjusting one or moreparameters of the process that are used to treat the first region torender it substantially free of the catalyst material. Once a desireddepth is achieved, e.g., to meet the desired performance characteristicsfor a particular end use application, the process is carefullycontrolled so that the first region depth in all remaining parts withinthe family of parts (made from the same material and processed in thesame manner) is the same. As noted above, a current method that is usedfor measuring the depth of the body first region is by destructivetesting, whereby the part is cut in half, polished or otherwiseprepared, and then is viewed and measured using a scanning electronmicroscope.

While this technique enables one to determine the depth of the firstregion with some degree of accuracy, it also results in the destructionof the part, which adversely impacts manufacturing costs and efficiency.Additionally, this process is time consuming as the user typicallymeasures the depth of the first region along the entire part diameter,and then takes the average of the measured points to arrive at theoverall part average thickness of the first region.

While the use of such destructive testing method is effective fordetermining the average depth of the first region 16 in the body of thedestroyed part, using such method on a regular basis is not practicalfor a large scale manufacturing processes due to both the large numberof parts destroyed, and the time involved with preparing and measuringeach such part. Ideally, it is desired that a measurement technique ormethod be adopted that permits the measurement of as many parts producedwithin a family as possible for the purpose of ensuring the performancecharacteristics of such part.

Additionally, the use of such destructive testing technique enables oneto only view the region depth at one location within the part and is notuseful in identifying any depth irregularities that may exist along theentire interface between the first and second regions, which depthirregularities (whether patterned or random) may have an unwanted impactthe desired performance characteristics of the part.

XRF is a technique that can be used to nondestructively measure thedepth of one or more identified regions in the construction in a mannerthat is accurate, and that is capable of providing depth informationacross the entire region or surface area being measured. XRF relies onbombarding a target material with x-ray energy provided from an x-rayexcitation source such as an e-ray tube or a radioactive source. Oncethe x-ray enters the material it is either absorbed by a target atom orscattered through the material.

When the x-ray is absorbed by a target atom, the atom transfers all ofits energy to an innermost electron, which mechanism is referred to asthe “photoelectric effect.” During this process, if the primary x-rayhas sufficient energy, electrons are ejected from the inner shells ofthe atom, creating vacancies or voids in the vacated shells. Thesevacancies present an unstable condition for the atom.

Electrons from the atom's outer shells are transferred to the innershells to return the atom to a stable condition. The process of electrontransfer from the outer shell to the inner shell produces acharacteristic x-ray having an energy that is the difference between thetwo binding energies of the corresponding shells. The x-rays emitted bythe target atom during this process are called X-ray fluorescence (XRF).The process of detecting and analyzing the emitted x-rays from thetargeted atoms is called XRF analysis. Depending on the particularapplication, XRF can be produced by using not only x-rays but also byusing other primary excitation sources like alpha particles, photon, orhigh-energy electron beams.

The energy level or wavelength of fluorescent x-rays emitted by thetarget atom within the material is proportional to the atomic number ofthe target atom, and is characteristic for a particular material. Thequantity of energy release via such emitted fluorescent x-rays is alsodependent upon the thickness or depth of the material being measured.

FIG. 3 illustrates an XRF device 24 as used to measure the depth of oneor more regions in the ultra-hard polycrystalline construction of FIGS.1 and 2. In an example embodiment, the device 24 comprises an x-raysource 26 and can include a fail-safe shutter 28 and a collimator 30.The collimator is used to direct an incident x-ray 32 onto a desiredsurface 34 of the ultrahard polycrystalline construction 36 that ispositioned on a suitable positioning assembly 38. In an exampleembodiment, the positioning assembly and/or the x-ray source can beconfigured to move if necessary to provide extended coverage over adesired region of the ultra-hard polycrystalline construction 36.

The device 24 further includes a proportional counter 40 that may bepart of or separate from the device. The proportional counter maycomprise a gas disposed within a counter tube, which gas is ionized bythe emission of x-rays or photons from the target material. The emittedx-rays or photons ionize gas in the counter tube that is proportional totheir energy, permitting spectrum analysis for determining the nature ofthe target material and its thickness.

In an example embodiment, the ultra-hard polycrystalline construction 36is oriented with the device 24 so that the device emits x-ray energyonto the surface 34 of the ultra-hard polycrystalline construction fromwhich the body first region extends. The device is configured having anx-ray source 26 selected to produce x-ray energy that will create a voidin the inner shell of the catalyst material that is present in the bodysecond region. In an example embodiment, the catalyst material iscobalt. In the event that the catalyst material in the second region issome other material, the x-ray source is selected to create a void inthe inner shell of such other catalyst material.

In an example embodiment, the device is configured to emit x-rays onto adesignated surface area of the ultra-hard polycrystalline constructionto produce XRF from the targeted atoms, e.g., the catalyst material inthe second region, within such designated surface area. X-rays that aregenerated by the device pass through the ultra-hard polycrystallineconstruction body first region and to the target atoms in the secondregion. The XRF emitted from the targeted atoms in the portion of thesecond region associated with the designated surface area is measured.In an example embodiment, the XRF emitted is an indication of thedistance from the surface 34 of the ultra-hard polycrystallineconstruction to the second region, or the thickness or depth of thefirst region.

This measurement data can be used to generate a plot of the first regionthickness within the designated surface area. The device can berepositioned relative to the construction and used multiple times toemit x-rays onto other surface areas of the ultra-hard polycrystallineconstruction to obtain desired measurement data and plot the firstregion thickness or depth at a number of different surface areas.Generally speaking, the surface area of the target material that iscovered by the device in one instance will vary depending on the size ofthe collimator. The larger the collimator the larger the surface areabeing covered and the fewer number of times that the device will need tobe repositioned and used to generate measurement data sufficient tocover the entire surface area of the target material, if such isdesired.

In an example embodiment, XRF is used as a first method or technique fornondestructively obtaining measurement data of an ultra-hardpolycrystalline construction first region thickness or depth. XRF ispreferably used as the first method because of its ability to providemeasurement data for the entire surface area of the first region thatcan be plotted to produce a topographical view of the interface betweenthe first and second regions within the construction.

Such a topographical view can be very helpful in identifying anyirregularities along the entire interface, i.e., in the first regionthickness or depth, that could exist and possibly be the source of anundesired performance characteristic. Additionally, the use of such atopographical plot can help to identify whether any such irregularitiesare in a arranged in pattern or are random, which can be useful for thepurpose of evaluating and/or controlling the process that is used toform the ultra-hard polycrystalline construction, e.g., to form the bodyfirst region.

FIG. 4 illustrates a plot 40 that is generated by using the XRF deviceof FIG. 3. The plot provides a topographical visual indication of thedepth along a portion of the body first region (or the distance from thesurface of the ultra-hard polycrystalline construction to the secondregion) within a predetermined surface area. In this example, the XRFdevice was used to generate a 400 point array scan of a surface area ofthe ultra-hard polycrystalline construction comprising a body having apolycrystalline diamond matrix first region substantially free of acatalyst material, and a PCD second region that includes a cobaltcatalyst material, wherein the target atom is cobalt. The designatedsurface area had a size of approximately 0.1 by 0.025 inches.

As illustrated in the plot 40, different depths along portion of thefirst region within this surface area are indicated bydifferently-colored regions 44, 46, 48, 50, 52, 54, 56 and 58. In anexample embodiment, a legend 60 is provided to match the colors of theplot to a corresponding numerical thickness. In the example embodimentthat is illustrated, the numerical data provided in the legend isprovided in dimensions of micrometers.

In an example embodiment, XRF is used as a first nondestructive testmethod for obtaining measurement data for the first region of anultra-hard polycrystalline construction representing a product family.More preferably, XRF is used as the first test method to obtainsufficient measurement data to provide a plot of the first regionthickness. Generation of the plot, such as that illustrated in FIG. 4,is used to evaluate whether there are any unwanted irregularities in thedepth of the first region that could impair product performance. Oncethe plot is generated, and the first region depth is determined to bewithin an acceptable standard, then the first region thickness for anumber of products in the same product family, i.e., products that areproduced from the same materials and in the same general manner, aresubsequently measured using a second nondestructive measurement method.

The second nondestructive measurement method is preferably one thatdemonstrates a good degree of accuracy, and can be used to relativelyquickly evaluate the thickness of a part to permit obtaining part firstregion thickness information on a number of parts in a relatively shortamount of time. In an example embodiment, the second nondestructivemeasurement method can be used on a designated number of parts withinthe part family, or on each part within the part family, to furtherensure that the first region thickness or depth of the parts within afamily is within a designated tolerance.

A first example second nondestructive measurement method or techniqueuseful with this invention is Beta Backscatter (BB). Referring to FIG.5, BB uses a device 62 that includes a radiation source 64 in the formof a beta-emitting isotope that is positioned to direct a beam of betaparticles 66 through an aperture 68. In an example embodiment, theradiation source and aperture can be packaged or combined together inthe form of a probe. The device aperture 68 is positioned onto a surface70 of the ultra-hard polycrystalline construction 72 is adjacent thefirst region 74. When the device is actuated, the beta particles 66enter the construction first region 74 and a proportion of the betaparticles are “backscattered” from the construction.

The backscattered particles 76 pass back through the aperture 68. Thebackscattered particles 76 penetrate a very thin window 78 of a GeigerMuller tube 80. The Geiger Muller tube 80 contains a gas that ionizeswhen the backscattered beta particles pass through the window. Thisionization causes a momentary discharge to occur across electrodes (notshown) disposed within the Geiger Muller tube 80. The discharge is inthe form of a pulse, and the device is configured to count the pulsesand translate them into a thickness measurement of the constructionfirst region 74.

Generally, materials with low atomic numbers backscatter the betaparticles at a significantly lower rate than materials with high atomicnumbers. When used with the ultra-hard polycrystalline material, betaparticles are scattered by both materials in the first region and thematerials beneath the second region, (please confirm that this statementis correct), and the material in the first region has an atomic numberthat is different from that of the material in region beneath the firstregion (please confirm that this statement is correct). If the thicknessof the first region changes, so does the backscatter rate. The change inthe rate of particles scattered is therefore a measure of the coatingthickness.

In an example embodiment, before the BB method of measuring is placedinto operation the device is calibrated by using a standard in the formof a construction having a known first region thickness. Once the BBdevice is calibrated it is placed into use to measuring the constructionfirst region thickness. A feature of using BB as the secondnondestructive measurement method is that once calibrated, it can beprovide a first region thickness measurement more quickly than by usingXRF, making it well suited for use production.

The number of parts in a family that are measured using BB, as well asthe number of locations on a part that are measured to provide anindication of the measured thickness for a part, will depend on a numberof factors such as the nature of the part itself, and/or the size of theBB probe or aperture, and/or the stability of the process used to makethe parts. For example, depending on the particular materialmicrostructure of the ultra-hard polycrystalline construction and/orpossible known irregularities in the first region thickness, e.g., asidentified using XRF, it may be necessary to use BB to take measurementdata at more that one location on the part to obtain an average firstregion thickness for the part.

The number of parts in a family that are measured, or the frequency ofpart sample measurement in a family, using BB may be influenced by thestability of the process used to make the parts. Generally, the morestable the process used to make the parts in a family the fewer thenumber of parts to be measured using this second nondestructive methodto obtain a desired level of certainty that the first region thicknessof the parts meets a predetermine standard.

A second example second nondestructive measurement method or techniqueuseful with this invention is X-ray radioscopy (XRR). Referring to FIG.6, XRR uses a device 82 that includes a radiation source 84 that isconstructed to emit and direct X-ray wavelength electromagneticradiation 86 onto a designated target. For use in this invention, theradiation source 84 is positioned generally perpendicular to theultra-hard polycrystalline construction 88. In an example embodiment,the X-ray source 84 is positioned to direct X-ray radiation 86 in adirection perpendicular to the ultra-hard polycrystalline construction,and specifically perpendicular to the first region 90.

As the X-rays pass through the construction, the different regions ofthe construction, e.g., the first region 90, the second region 92, andthe substrate 94, absorb different amounts of the X-ray radiation, thusallow respectively different amounts of the X-ray radiation to passtherethrough. The X-ray radiation 96 exiting the construction is passedto a detecting source 98. In an example embodiment, the detecting sourcecan be provided in the form of photographic film, semiconductor plates,image intensifiers, or electronic hardware capable of creating,displaying and/or storing an electronic image of the X-rayedconstruction. Thus, the XRR device is configured to produce a visualimage of the construction showing its different regions.

FIG. 7 illustrates an image 100 provided by an XRR device as used tonondestructively measure the thickness of the construction first region90. In an example embodiment, the image is one that is generatedelectronically from the X-ray radiation received from the constructionand displayed on a suitable electronic display monitor. The image 100provides an area plot of the construction volume, or in essence a shadowof the construction and its variation in density within the differentconstruction regions.

In an example embodiment, the image 100 provided by the XRR devicecomprises a first image section 102 that corresponds to the constructionfirst region 90, that is the lightest and that has the highest degree ofexposure due to the absence of the catalyst material. The image 100comprises a second image section 104 that corresponds to theconstruction second region 92, that that is relatively darker and thathas a lower degree of exposure than the first region due to the presenceof the catalyst material. The image 100 comprises a third image section106 that corresponds to the construction substrate 94, that isrelatively darker and that has a lower degree of exposure than thesecond region due to the heavy metal content in the substrate, e.g.,when using a WC—Co substrate.

Because the X-ray radiation generated by the device 82 is directedradially through the entire diameter of the target construction, thedifferent sections presented in the image 100 represent an averagethickness of each of the respective regions within the construction.Once the XRR device is properly calibrated, e.g., using a standardconstruction having regions of known thicknesses, one is able to measurefrom the image the bulk thickness of each construction region. As usedherein, the term “bulk thickness” is understood to mean the averagethickness of the particular region for the part. Thus, a feature ofusing the XRR device and method for nondestructively measuring theconstruction is that, unlike the destructive test method that onlyprovides region thickness information along a diametric section throughthe construction, its provides a projected area image of theconstruction and its different regions.

Another method that can be used to increase the XRR is by narrowing theX-ray beam using a collimator or the like to produce a generallyline-shaped beam as opposed to a pyramid or conical shaped beam. Whenthe XRR device is configured in this manner, the line-shaped beam isgenerally aligned with a top surface of the object to be measured andthe object is mounted on a precision translation table. The table isused to move the object vertically through the source beam, thusprojecting a series of line plots to create an area plot of the targetedregion with a much reduced geometric error. This system can beprogrammed to capture a transition zone within the object, e.g., betweentwo adjacent regions within the object, and provide an output from atranslation axis that can be correlated to the depth of the targetedregion being measured.

If desired, to increase the statistical confidence that the imagecaptures the average thickness of each construction region, the XRRdevice can be used multiple times with the construction being rotated,e.g., three images of the construction could be taken with theconstruction being rotated 120 degree for each image. Also, to increasestatistical confidence, one can apply a computer tomography (CT) methodto create a 3-D image of the construction. As illustrated in FIG. 7, theaverage thickness of the construction first region can be determinedfrom the image by measuring the distance “D” from the surface 108 of thefirst image section 102 to the interface 110 with the second region 104.

This measurement can be performed manually by the user or can be doneautomatically, e.g., through the use of a computer software program suchas one designed to calculate an average value from the electronic datarepresenting an image section. In an example embodiment, the averagevalue for a desired construction region thickness is determinedautomatically, e.g., through the use of such computer software. Ifdesired, such software can further be configured to receive a userinput, e.g., a target region thickness or the like, and provide a useroutput that compares the average measured thickness to the targetthickness for the purpose of evaluating whether the constructionconforms with the target thickness.

In an example embodiment, XRF is used as a first nondestructive methodfor measuring the thickness of a desired region within an ultra-hardpolycrystalline construction that is part of a family of constructionsthat have been made using the same materials and by using the sameprocess of manufacture. The exact number of parts within a can will varyon a number of factors such as the types of materials used to form theconstruction, the number of total needed parts needed for the end-useapplication, and the process that is used to form the parts.

The XRF device is used to obtain detailed measurement information alongthe region of the construction of interest. In an example embodiment,XRF is used to obtain a typographical plot of the region thickness toprovide measurement information along a substantial area of theconstruction. This detailed measurement information is useful fordetermining whether the construction region thickness displays anyunwanted irregularities that may operate to impair operating performanceof the construction.

In an example embodiment, BB and/or XRR can be used as a secondnondestructive method for measuring the thickness of a desired regionwithin a number of the ultra-hard polycrystalline constructions or partsthat are within the same family of the part that was measured using XRF.The use of such second nondestructive methods is desired for testing oneor more of the remaining parts within the family of parts because thesemethods enable region thickness data to be obtained relatively quicklywhen compared to using XRF, thereby allowing for the efficient regionthickness measurement of many parts, e.g., promoting use in a productionenvironment.

In addition to BB and XRR, other nondestructive measurement methods canbe used as a second nondestructive method for this invention, such as byeddy current (EC), magnetic induction (MI), and microresistance (MR).

EC uses the principal of electromagnetism as the basis for conducting anondestructive measurement of the target ultra-hard polycrystallinematerial. FIG. 8 illustrates an EC device 100 comprising a probe 102that is positioned over a surface 104 of the object 106 to be measured,e.g., a surface of an ultra-hard polycrystalline construction, and isoperated to generate eddy currents in the object through a process ofelectromagnetic induction. The probe 102 is connected to and alternatingcurrent (AC) source 103, and is operated to direct an alternatingcurrent (AC) magnetic field onto the object. This magnetic field expandsas the alternating current rises to maximum and collapses as the currentis reduced to zero. When the object 106 is positioned in close proximityto the probe 102 and the changing magnetic field, eddy currents 108 willbe induced in the object. Such eddy currents are induced electricalcurrents that flow in a circular path, and occur in the object 106 inproportion to the frequency of the AC magnetic field and resistivity ofthe object material. The induced eddy currents generate an opposingmagnetic field that alters the circuit reactance and the output voltageof the probe 102. The change in output voltage is measured and is usedto calculate the target region thickness in the object 106.

FIG. 9 illustrates a MI device 110 comprising a probe 112 in the form ofa transformer circuit comprising a primary circuit 114 that is connectedto an AC source 116, and a secondary circuit 118 that is connected to anamplifier or the like 120. The probe 112 is positioned adjacent asurface 122 of an object 124 to be measured. The system reacts to thepresence of a target material in the object, e.g., a target materialplaced within a region of an ultra-hard polycrystalline materialdisposed beneath a surface region. The circuit efficiency and outputvoltage increase when the probe 112 is brought near the surface 122 ofthe object 124, providing parameters that can be used to measure thethickness of the region above the region containing the target material.

MR is a technique that can be used to determine the thickness of aregion within an object, e.g., an ultra-hard polycrystalline material,from resistance calculations. Initially, precise resistance measurementsare taken of an object having a known region thickness, e.g., astandard. Once this parameter is known, it is combined with other datafrom the object to calculate the average region thickness. Thesecalculations can be performed automatically by software associated withthe measurement device. Specially designed electrically isolated probetips are then used to simultaneously inject current and take voltagedrop measurements along the surface of the object to be measured.Resistance from these measurements is then calculated by Ohm's Law andare correlated to the standard to determine the measured thickness ofthe object.

While the nondestructive methods described herein have been described asbeing useful to measure the thickness of one or more regions within anultra-hard polycrystalline material, and more specifically to measurethe thickness of a region that is substantially free of catalystmaterial, it is to be understood that the nondestructive methodsdescribed herein can be used to measure the thickness of any regionwithin such constructions. Such regions mayor may not include a catalystmaterial. For example, the nondestructive methods described herein canbe used to measure the thickness of one or more regions within theconstruction having the same general ingredients but differentproportions of the ingredients. For example, when the ultrahardpolycrystalline construction is PCD, the nondestructive methods of thisinvention can be used to measure the thickness or one or more differentPCD regions characterized by having different diamond volume contents.

Additionally, while the nondestructive methods of this invention havebeen described in the context of being useful to measure a regionthickness extends a depth from a particular surface, e.g., a front sidesurface, of ultra-hard polycrystalline material, it is to be understoodthat the nondestructive methods of this invention can be used to measureregion thicknesses that extend from other surfaces of the constructionin addition to or apart from the construction front side surface. Forexample, nondestructive methods of this invention can be used to measurethe region thickness extending from a bevelled or chamfered surface ofthe construction that is oriented at an angle to the front side surface,and/or extending from a sidewall surface extending axially between thefront side surface of the construction to the substrate.

The nondestructive methods described herein can be used tonondestructively measure the depth or thickness of one or more regionsof ultra-hard polycrystalline constructions that are configured for usein a number of different applications, such as tools for mining,cutting, machining and construction applications. Such ultra-hardpolycrystalline constructions are particularly well suited for formingworking, wear and/or cutting components in machine tools and drill andmining bits such as roller cone rock bits, percussion or hammer bits,diamond bits, and shear cutters.

FIG. 10 illustrates an embodiment of an ultra-hard polycrystallineconstruction, comprising one or more regions within the body that can bemeasured using the nondestructive methods described above, provided inthe form of an insert 126 used in a wear or cutting application in aroller cone drill bit or percussion or hammer drill bit. For example,such inserts 126 are constructed having a substrate portion 128, formedfrom one or more of the substrate materials disclosed above, that isattached to a body 130 having first and second regions as describedabove. In this particular embodiment, the insert comprises a domedworking surface 132, and the first region is positioned along theworking surface and extends a selected depth therefrom into the body. Inan example embodiment, the insert can be pressed or machined into thedesired shape or configuration prior to the treatment for removing thecatalyst material from the first region. It is to be understood thatultra-hard polycrystalline constructions can be configured as insertshaving geometries other than that specifically described above andillustrated in FIG. 10.

FIG. 11 illustrates a rotary or roller cone drill bit in the form of arock bit 134 comprising a number of the wear or cutting inserts 126disclosed above and illustrated in FIG. 10. The rock bit 134 comprises abody 136 having three legs 138 extending therefrom, and a roller cuttercone 140 mounted on a lower end of each leg. The inserts 126 are thesame as those described above comprising the ultra-hard polycrystallineconstruction, and are provided in the surfaces of each cutter cone 140for bearing on a rock formation being drilled.

FIG. 12 illustrates the insert 126 described above and illustrated inFIG. 10 as used with a percussion or hammer bit 142. The hammer bitgenerally comprises a hollow steel body 144 having a threaded pin 146 onan end of the body 144 for assembling the bit onto a drill string (notshown) for drilling oil wells and the like. A plurality of the inserts126 are provided in the surface of a head 148 of the body 144 forbearing on the subterranean formation being drilled.

FIG. 13 illustrates an ultra-hard polycrystalline construction measuredusing the nondestructive methods described above as embodied in the formof a shear cutter 150 used, for example, with a drag bit for drillingsubterranean formations. The shear cutter 150 comprises an ultra-hardpolycrystalline body 152 that is sintered or otherwise attached to asubstrate 154. The body 152 includes a working or cutting surface 156that is formed from the construction first region. The working orcutting surface of the shear cutter can extend from the upper surface toa bevelled surface defining a circumferential edge of the cutter and/orcan extend along a sidewall surface of the cutter. The constructionfirst region can extend a depth from such working surfaces. It is to beunderstood that ultra-hard polycrystalline constructions can beconfigured as shear cutters having geometries other than thatspecifically described above and illustrated in FIG. 13.

FIG. 14 illustrates a drag bit 158 comprising a plurality of the shearcutters 150 described above and illustrated in FIG. 13. The shearcutters 150 are each attached to blades 160 that extend from a head 162of the drag bit for cutting against the subterranean formation beingdrilled. Because the shear cutters of this invention include a metallicsubstrate, they are attached to the blades by conventional method, suchas by brazing or welding.

Other modifications and variations of using nondestructive methods tomeasure the thickness or depth of one or more regions within ultra-hardpolycrystalline constructions will be apparent to those skilled in theart. It is, therefore, to be understood that within the scope of theappended claims, this invention may be practiced otherwise than asspecifically described.

1. A system for nondestructively obtaining measurement information fromone or more ultra-hard polycrystalline constructions comprising: anultra-hard polycrystalline construction comprising an ultra-hardpolycrystalline body that is attached to a metallic substrate; an x-raysource for producing and transmitting x-ray energy onto the constructionduring one step of using the system; a proportional counter forreceiving x-ray fluorescence emitted by the construction from whichmeasurement information is derived; and a device different from the oneused to derive measurement information from x-ray fluorescence tonondestructively obtain measurement information from the constructionduring another step of using the system; wherein the measurementinformation denotes a thickness of a region within the ultra-hardpolycrystalline body, or an interface between adjacent regions in theultra-hard polycrystalline body.
 2. The system as recited in claim 1wherein the ultra-hard polycrystalline body is polycrystalline diamond,and wherein the x-ray energy is directed onto a region of the body. 3.The system as recited in claim 2 wherein the ultra-hard polycrystallinebody comprises a region that does not include a catalyst material usedto sinter the body.
 4. The system as recited in claim 3 wherein theultra-hard polycrystalline body comprises a region that includes acatalyst material.
 5. The system as recited in claim 4 wherein themeasurement information relates to the region that includes the catalystmaterial.
 6. The system as recited in claim 5 wherein the measurementinformation relates to the location of the catalyst material within thebody.
 7. The system as recited in claim 1 wherein the device comprisesone obtaining measurement information by techniques selected from thegroup consisting of beta backscatter, x ray radioscopy, eddy current,magnetic induction, and microresistance.
 8. The system as recited inclaim 1 wherein the ultra-hard polycrystalline body comprisespolycrystalline diamond, wherein a region of the body adjacent thesubstrate includes a catalyst material, and wherein the measurementinformation relates to the location of the catalyst material within thebody.
 9. The system as recited in claim 8 wherein a region of thediamond body extending away from the region comprising the catalystmaterial and towards a surface of the body is substantially free of thecatalyst material.
 10. The system as recited in claim 9 wherein thewherein the measurement information relates to the location of aninterface between the region comprising catalyst and the regionsubstantially free of the catalyst.
 11. A method for nondestructivelyobtaining measurement information from within an ultra-hardpolycrystalline construction, comprising the steps of: conducting ameasurement using a device comprising an x-ray source and x-rayfluorescence detector by directing x-ray energy onto a surface of a bodyof the construction, wherein the body comprises polycrystalline diamondand wherein the body is attached to a metallic substrate, wherein thebody includes a first region that is substantially free of a catalystmaterial used to form the body, and a second region that includes thecatalyst material, wherein x-ray fluorescence is emitted from the body,and wherein measurement information is derived from the x-rayfluorescence; and conducting another measurement of the constructionusing a nondestructive technique selected from the group consisting ofbeta backscatter, x-ray radioscopy, eddy current, magnetic induction,and microresistance; wherein the measurement information denotes athickness of a region within the ultra-hard polycrystalline body, or aninterface between adjacent regions in the ultra-hard polycrystallinebody.
 12. The method as recited in claim 11 wherein the measurementinformation derived from the x-ray fluorescence is related to thelocation of the catalyst material within the body.
 13. The method asrecited in claim 11 wherein the measurement information derived from thex-ray fluorescence relates to the thickness of the first region.
 14. Themethod as recited in claim 11 wherein the second region is disposedwithin the body adjacent the substrate, and the first region extendsfrom a working surface of the body.
 15. The method as recited in claim11 comprising the further step of generating a map displaying themeasurement information.
 16. The method as recited in claim 11 whereinthe x-ray fluorescence is emitted from a target atom that is present inthe body.
 17. The method as recited in claim 16 wherein the target atomis present in the second region but not in the first region.
 18. Themethod as recited in claim 16 wherein the target atom is selected fromthe Group VIII elements of the Periodic table.
 19. A system forobtaining measurement information from within an ultra-hardpolycrystalline constructions comprising: an ultra-hard polycrystallineconstruction comprising a polycrystalline diamond body that is attachedto a metallic substrate, the body including a region that issubstantially free of a catalyst material used to sinter the body athigh pressure-high temperature conditions; an x-ray source positionedadjacent the body for producing and transmitting x-ray energy onto bodyduring one step of using the system; a proportional counter positionedadjacent the body for receiving x-ray fluorescence emitted by the bodyfrom which measurement information is derived; and a device differentfrom the one used to derive measurement information from x-rayfluorescence to obtain measurement information from the constructionduring another step of using the system; wherein the measurementinformation denotes a thickness of a region within the ultra-hardpolycrystalline body, or an interface between adjacent regions in theultra-hard polycrystalline body.
 20. The system as recited in claim 19wherein the body comprises a region comprising the catalyst material,and wherein the measurement information relates to the location of thecatalyst material within the body.